In article , Jim Yanik wrote:
(Doug Miller) wrote in
:

In article
,
wrote:
On Mar 2, 9:01=A0pm, (Doug Miller) wrote:
In article ,
(Don =
Klipstein) wrote:
In , Doug Miller wrote:
The thing that really stood out to me was the statement by
Toyota's president that they're going to look into programming a
brake override for the throttle.

I have only one question: WHY IN GOD'S NAME WAS THAT NOT THERE
FROM THE BEGINNING?

=A0*Programming* a throttle override by the brake? =A0As in
relying on =
lack
of electronic malfunction in order to have the brake reliably apply
an override onto the throttle?

Since the override becomes necessary only in the event of a throttle
malfunction, for the override to not work would require a second
malfunction. Clearly two simultaneous malfunctions are *far* less
likely than any single malfunction.


That's obviously totally false.

No, in fact, that's an elementary principle of probability theory: any
two events in combination are less likely to occur than either one of
them alone.

only problem is that in this case of throttle control programming,both
"events" are all part of the *same code*.
it's still possible for the code to jump off into nowhere, go into some
strange loop.

And the failure rates of the processor, its RAM, whatever the code is
stored in, and power and ground connections to these and any power
conditioning circuitry / components such as voltage regulators and
bypass capacitors are not going to zero. The power conditioning for the
throttle control computer may be insufficient to handle voltage variations
caused by malfunction or failure elsewhere in the car. Hardware
failure/malfunction can cause the software/firmware to malfunction or not
be any good at all.

(Will the computer that controls the throttle work properly at the
lowest voltage that the ignition system can work at? If the alternator's
voltage regulator fails, will the computer that controls the throttle keep
on ticking at 17 volts-plus or whatever until the battery is dried out or
fried enough to not allow the car to run or the high voltage blows
something in a way that stops the engine? Will the computer control the
throttle properly with the worst corrosion at the battery terminals that
allows the car to run?)

- Don Klipstein )